<?php
/*
 *  $Id$
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

/**
 * Doctrine_Query_Filter_Chain
 *
 * @package     Doctrine
 * @subpackage  Query
 * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @link        www.doctrine-project.org
 * @since       1.0
 * @version     $Revision$
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 */
class Doctrine_Query_Filter_Chain
{
	/**
	 * @var array $_filters         an array of Doctrine_Query_Filter objects
	 */
	protected $_filters = array();

	/**
	 * add
	 *
	 * @param Doctrine_Query_Filter $filter
	 * @return void
	 */
	public function add(Doctrine_Query_Filter $filter)
	{
		$this->_filters[] = $filter;
	}

	/**
	 * returns a Doctrine_Query_Filter on success
	 * and null on failure
	 *
	 * @param mixed $key
	 * @return mixed
	 */
	public function get($key)
	{
		if ( ! isset($this->_filters[$key])) {
			throw new Doctrine_Query_Exception('Unknown filter ' . $key);
		}
		return $this->_filters[$key];
	}

	/**
	 * set
	 *
	 * @param mixed $key
	 * @param Doctrine_Query_Filter $listener
	 * @return void
	 */
	public function set($key, Doctrine_Query_Filter $listener)
	{
		$this->_filters[$key] = $listener;
	}

	/**
	 * preQuery
	 *
	 * Method for listening the preQuery method of Doctrine_Query and
	 * hooking into the query building procedure, doing any custom / specialized
	 * query building procedures that are neccessary.
	 *
	 * @return void
	 */
	public function preQuery(Doctrine_Query $query)
	{
		foreach ($this->_filters as $filter) {
			$filter->preQuery($query);
		}
	}

	/**
	 * postQuery
	 *
	 * Method for listening the postQuery method of Doctrine_Query and
	 * to hook into the query building procedure, doing any custom / specialized
	 * post query procedures (for example logging) that are neccessary.
	 *
	 * @return void
	 */
	public function postQuery(Doctrine_Query $query)
	{
		foreach ($this->_filters as $filter) {
			$filter->postQuery($query);
		}
	}
}